/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cocoon.spring.configurator;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.apache.cocoon.spring.configurator.impl.ServletContextFactoryBean;
/**
* Utility class to manage hierarchical application contexts.
*
* @version $Id: WebAppContextUtils.java 606207 2007-12-21 14:17:33Z vgritsenko $
* @since 1.0
*/
public abstract class WebAppContextUtils {
/** The name of the request attribute containing the current bean factory. */
public static final String CONTAINER_REQUEST_ATTRIBUTE = WebAppContextUtils.class.getName();
/**
* Get the current web application context.
*
* @throws IllegalStateException if no WebApplicationContext could not be found
* @return The current web application context.
*/
public static WebApplicationContext getCurrentWebApplicationContext() {
final RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
return getCurrentWebApplicationContext(attributes);
}
/**
* Return the current web application context or if the attributes are null, the parent context.
*
* @param attributes The request attributes.
* @throws IllegalStateException if no WebApplicationContext could not be found
* @return The web application context.
*/
protected static WebApplicationContext getCurrentWebApplicationContext(RequestAttributes attributes) {
if (attributes != null) {
Object obj = attributes.getAttribute(CONTAINER_REQUEST_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
if (obj != null) {
return (WebApplicationContext) obj;
}
}
// return the root context
return WebApplicationContextUtils.getRequiredWebApplicationContext(ServletContextFactoryBean.getServletContext());
}
/**
* Notify about entering this context.
*
* @param webAppContext The current web application context.
* @return A handle which should be passed to {@link #leavingContext(WebApplicationContext, Object)}.
*/
public static Object enteringContext(WebApplicationContext webAppContext) {
// get request attributes
final RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
// save current class loader and web application context
final ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();
final WebApplicationContext oldContext = (WebApplicationContext) attributes.getAttribute(CONTAINER_REQUEST_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
// set new class loader and context
attributes.setAttribute(CONTAINER_REQUEST_ATTRIBUTE, webAppContext, RequestAttributes.SCOPE_REQUEST);
Thread.currentThread().setContextClassLoader(webAppContext.getClassLoader());
return new ContextInfo(oldContext, oldClassLoader);
}
/**
* Notify about leaving this context.
* @param webAppContext The current web application context.
* @param handle The returned handle from {@link #enteringContext(WebApplicationContext)}.
*/
public static void leavingContext(WebApplicationContext webAppContext, Object handle) {
if (!(handle instanceof ContextInfo)) {
throw new IllegalArgumentException("Handle must be an instance of ContextInfo and not " + handle);
}
final ContextInfo info = (ContextInfo) handle;
// get request attributes
final RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
// restore class loader and previous web application context
Thread.currentThread().setContextClassLoader(info.classLoader);
if (info.webAppContext == null) {
attributes.removeAttribute(CONTAINER_REQUEST_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
} else {
attributes.setAttribute(CONTAINER_REQUEST_ATTRIBUTE, info.webAppContext, RequestAttributes.SCOPE_REQUEST);
}
}
/**
* Private bean keeping track of the class loader and web application context.
*/
protected static final class ContextInfo {
public final ClassLoader classLoader;
public final WebApplicationContext webAppContext;
public ContextInfo(WebApplicationContext w, ClassLoader c) {
this.classLoader = c;
this.webAppContext = w;
}
}
}